Model output discussion - Closing in on Christmas

[Fourty Point Three Degrees]

Looking at some of the current charts i really dont see why people are getting excited over cold rain /sleet on xmas day. The 850s dont look low enough to deliver snow.  Still theres time for things to get colder (or warmer). 

[Mike Poole]

1 minute ago, chionomaniac said:

Plenty of time for this to deteriorate before T+0. But I’m optimistic. Plenty of time to improve too.  I don’t worry about 850’s either being marginal, because small shifts here and there can make a big difference. Just be grateful that the PV is still in turmoil and too big a difference compared to the ECM to worry exactly how it will play out. 

Yes, agree with the last point this run and the ECM are as chalk and cheese, trouble is I’m not sure which one is the chalk and which one is the cheese!  More runs needed, but we have many cold irons in the fire (what am I talking about??!) so fascinating to see how it pans out over Christmas and beyond.

[Scott Ingham]

4 minutes ago, Uncertainy said:

Took your advice Scott and took a few days off the models due to the inevitable fluctuations in the modelling in resolving the  Arctic high, extent of Atlantic ridging and the size and shape of the trough exiting the UK - the latter of which gave NW England 80, yes 80 hours of continuous rain on the 13.12.20 GFS 18z

The present GFS  iteration looks like an Xmas day UK high which again would be a fine call Scott. I’ve learnt loads from your input recently mate so keep it up!

None of the above model tribulations have actually been fully resolved but this evening’s trends look good, we have:

 - A stronger Atlantic ridge on the ECM mean at days 8-10 vs this morning, with a better trend for Euro troughing in the extended as BA alluded to - apparent on the GEPS too.

- A glorious ECM op which, despite @Steve Murr’s long shot can’t be discounted. PS Steve whilst I totally understand your family/work based reasoning (am a working single dad myself) to post less, the knowledge, passions and enthusiasm for weather that you and others on this forum share has helped inspire me to learn about Meterology. Any and all input you are able to  continue to give, however infrequent, is very gratefully recieved!

- An improved GFS on the 12z, with these improvements showing up early in the run serving to squash the troublemaker low southwards and build better heights in behind. The southeast almost hits the Jackpot at day 9!

Finally a note on the EC 46, the surface temp anomaly was quite striking for weeks 3 and 4

Week 3

Week 4

Cold becoming quite extensive over NW Europe.
Adds credence to the ‘the best is yet to come’ from this fascinating festive setup we have. 

Thanks mate we shall see. The UK high thinking is a blend of MJO 5 in a nina background. The nina signal when the tropical signal isnt there is to pull the azores north and west. MJO 5 is to create a scandi but more european high. The signal was in low amplitude so i had a blend of opposing signals which is to create a mid lat high. However what was also to factor in was the weakness of the PV. This has allowed our UK high to sit a little higher in latitude. 

Now the signal in 6 and 7 is to send this high then north west.

Now again. Its not high amplitude but factor in a polar vortex weak for the time of the year and torque events coming in one after the other and our next move should be Greenland and then icelandic heights as the tropical signal wanes 

[BLIZZARDMAN]

Way out in FI but look at the difference....

[Zak M]

3 minutes ago, 38.7°C said:

Looking at some of the current charts i really dont see why people are getting excited over cold rain /sleet on xmas day. The 850s dont look low enough to deliver snow.  Still theres time for things to get colder (or warmer). 

What model(s) are you looking at?

I think there’s a decent chance for some snow on lower ground on Christmas Day if the ECM or GFS verify.

Edited December 15, 2020 by Zak M

[Anthony Burden]

One thing certain very much a guessing game regarding charts after 120 hrs /144hrs

The only thing that seems to be constant is the cold theme over Christmas.

Not bad let’s sit back and enjoy this roller coaster.

[tight isobar]

5 minutes ago, 38.7°C said:

Looking at some of the current charts i really dont see why people are getting excited over cold rain /sleet on xmas day. The 850s dont look low enough to deliver snow.  Still theres time for things to get colder (or warmer). 

Aye ??!your obviously on the sauce ??!. Those overheads and wind points/flow are nigh on txt book.. @precipatation =snow.. its a world away in modelling.. but we keep chomping at the bit.. and this or even better evolution awaits imo.. we’ll see aye??!!

Edited December 15, 2020 by tight isobar

[Cheshire Freeze]

5 minutes ago, Snowman. said:

Russian high competing for the northern hemisphere at this point, very very large!

Going forward, the strat would be toast on this run

[Allseasons-Si]

1 minute ago, BLIZZARDMAN said:

Way out in FI but look at the difference....

...it's laughable and always is...at that range

fun to look at though.

it's a stonker though in fl.

 

 

[kold weather]

2 minutes ago, Zak M said:

What model(s) are you looking at?

I think there’s a decent chance for some snow on lower ground on Christmas Day if the ECM or GFS verify.

Yes should be cold enough, might be marginal close to the coast but in any decent strength shower there should be snow, especially overnight.

[chionomaniac]

The GFS often takes a new signal and overblown it tremendously. Then in the next few runs it modifies and retreats to go back to the old signal, but with the new signal incorporated. Probably occurring now

[Hotspur62]

Just the 14 pages today on this forum proves there is a bit of interest going forward.There certainly is a trend for colder weather commencing around the 23rd but I think it is wise to wait till the weekend before we can have any degree of confidence on this theme.My gut feeling is for it to be a cold crisp Xmas day if I had to have a punt but it is encouraging to see that we cannot rule out the threat of snow which hasnt happened many times in the 21st century for the UK.As we contemplate things I see the biggest Nor Easter is due to hit NE USA tomorrow with upto 18 inches of snow possible in some places-it could be biggest storm since 2009 as per Joe Bastardi !

[BarometerCat]

4 minutes ago, 38.7°C said:

Looking at some of the current charts i really dont see why people are getting excited over cold rain /sleet on xmas day. The 850s dont look low enough to deliver snow.  Still theres time for things to get colder (or warmer). 

It’s exciting because if it just happened to verify close to that we would see a colder Boxing Day etc... at this range it is still about trends. It’s very positive for a change! The evolution is interesting.

[danm]

5 minutes ago, BLIZZARDMAN said:

Way out in FI but look at the difference....

The definition of chalk and cheese. 

[feb1991blizzard]

Just now, CreweCold said:

Going forward, the strat would be toast on this run

There was an attempt at bringing cold in at this time in the 08/09 winter, i am beginning to think this has 09 written all over it, re-strengthening of vortex Jan before feb delivers - analogues 91 and 09 at this point.

[Scott Ingham]

2 minutes ago, chionomaniac said:

The GFS often takes a new signal and overblown it tremendously. Then in the next few runs it modifies and retreats to go back to the old signal, but with the new signal incorporated. Probably occurring now

Are you thinking more scandi than Greenie heights? Ive got Greenland toppling into icelandic in my head after Christmas.

[BelgianBlizzard]

 

Maybe, just maybe a white christmas for my hometown in Belgium

[Cold Winter]

Gorgeous run out in FI... but it should come with an 18+ rating

[Ice Day]

4 minutes ago, CreweCold said:

Going forward, the strat would be toast on this run

Along with the strat being toast, the PV is being pulled, pushed and stretched all over the show.... Alaskan high nosing in now!  This really is the pub run at full steam, terrific entertainment.

[Allseasons-Si]

Turn for the SE in phase one...

turn tor the NE in phase two...

all roads lead to cold on this run..lets not hope it is in Italy

[Kirkcaldy Weather]

Purely just for commenting on given the time frame, tho I do think blocked charts will continue to appear as we go toward the new year and beyond with the increasing warming strat which I done a rough estimate in the strat thread earlier, 1070 hpa block across Siberia and also trying to get a split tpv from the pacific too, previous run had a 1050 hpa high going into the Arctic from the Siberian side, quite a few positive signs appearing currently. 

Edited December 15, 2020 by Kirkcaldy Weather

[BLAST FROM THE PAST]

This run keeps on giving.....That’ll do me until 0700.  Another day ticked off.

I’m very impressed with the accuracy of the 18z

 BFTP

Edited December 15, 2020 by BLAST FROM THE PAST

[feb1991blizzard]

That is a stonking pacific ridge on the 18z, only a matter of time before the PV is destroyed and an SSW occurs if we got to that point.

[kold weather]

5 minutes ago, chionomaniac said:

The GFS often takes a new signal and overblown it tremendously. Then in the next few runs it modifies and retreats to go back to the old signal, but with the new signal incorporated. Probably occurring now

Yes the GFS I think was a little gungho with trying to smash the PV through to the east (it won't be the first time its tried and failed with that trick).

I'm getting a little bit Xmas 2005 vibes here with the modelling. That ended up somewhat downgrading as we moved closer to the time but then slightly remerging again towards the date as the high didn't get quite as far NE as expected.

[Cold Winter]

Just look at this... definitely won’t happen like this, or probably even close, but beautiful to see! I’ll have whatever the 18z is drinking